Structure and magnetic properties of stoichiometric and RE-rich NdY-Fe-B alloy ribbons

• Published in: Journal of magnetism and magnetic materials 2024-09, Vol.606, p.172381, Article 172381
• Main Authors: Fan, Sining, Xia, Puyue, Zhang, Wenhao, Wang, Zhaomeng, Wei, Geng, Zhang, Li, Xu, Wei, Shi, Yangguang, Tang, Shaolong
• Format: Article
• Language: English
• Subjects: Magnetic properties; Melt spinning; Nd-Y-Fe-B; Phase constitution
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2024.172381

•At higher wheel speeds, (Nd0.7Y0.3)11.8Fe82.3B5.9 alloys (RE11.8) transition to a single 2:14:1 phase.•At higher wheel speeds, (Nd0.7Y0.3)16.1Fe78B5.9 alloys (RE16.1) is composed of RE-rich phase and the 2:14:1 phase.•The increase in coercivity of the annealed RE11.8 alloy is due to the crystallization of the amorphous phase.•The reduction in coercivity of the annealed RE16.1 alloy is due to the diffusion of Y from RE-rich phase into the grains. Here we study the effect of rare earth (RE) contents on melt-spun and annealed NdY-Fe-B alloys, aiming to illustrate their phase structure, microstructure, and magnetic properties. The phase composition of RE11.8 alloys changes to a single 2:14:1 phase with increased wheel speeds. However, besides the 2:14:1 phase, the RE-rich phase can still be detected in RE16.1 alloys after increasing the wheel speeds. For ribbons prepared at 20 m/s, annealing promotes the generation of ultrafine primary grains in the RE11.8 alloys and subsequent grain growth, which leads to an increase and then a decrease in the coercivity of the alloys in the temperature range from 500 °C to 800 °C. The RE16.1 alloys consist of two phases after annealing, wherein the magnetic isolation of the RE-rich grain boundary phase relative to hard magnetic grains results in higher coercivity compared to the RE11.8 alloy. The preference of Y to enter the main phase grains rather than the RE-rich grain boundary phase leads to a decrease in the coercivity of RE16.1 alloys after annealing. These results provide new insights into the design and the development of Y-substituted Nd-Fe-B alloys.